The integrated circuit (IC) industry has experienced exponential growth. Technological advances in IC materials and design have produced generations of ICs, where each generation has smaller and more complex circuits than the previous generation. In the course of IC evolution, functional density (i.e., the number of interconnected devices per chip area) has generally increased while geometry size (i.e., the smallest component (or line) that can be created using a fabrication process) has decreased. This scaling down process generally provides benefits by increasing production efficiency and lowering associated costs.
Such scaling down has also increased the complexity of processing and manufacturing ICs and, for these advances to be realized, similar developments in IC processing and manufacturing are needed. For example, extreme ultraviolet lithography (EUVL) has become an important technique for implementing high-resolution lithography processes. While existing EUVL apparatuses and methods have been generally adequate, they have not been entirely satisfactory in every aspect. In one example, an EUV target material can contaminate components of a source vessel during a lithography exposure process, thereby shortening the lifetime of the components and necessitating maintenance procedures that require interruption of the lithography exposure process. Thus, improvements in this aspect are desired.